Poly (3,4-alkylenedioxythiophene) -based capacitors using ionic liquids as supporting electrolytes

ABSTRACT

A supercapacitor comprising a poly(3,4-ethylendioxythiophene) (PEDOT) and poly(3,4-propylenedioxythiophene) (PProDOT) as electrode couples for the capacitor and a pair of gel electrolyte layers disposed between the electrodes. The gel electrolytes are separated by a battery paper and are selected from a group consisting of a lithium salt and an organic electrolyte.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to the field ofelectroactive polymer devices, and, in particular, to a dual conductingpolymer charge storage devices/supercapacitors fabricated frompoly(3,4-propylenedioxythiophene) and poly(3,4-ethylenedioxythiophene)which operate as electrode couples.

[0003] 2. Description of the Prior Art

[0004] Electroactive polymer devices, in which the polymers store chargeand are switched between redox states, have been the object of intenseresearch over the past several years. As these polymers have thepossibility of being switched between their neutral form, a p type dopedoxidized form, and an n-type doped reduced form, a variety of electrodeconfigurations are possible and highly desirable. This has beenillustrated by the use of electroactive polymers in supercapacitors,rechargeable storage batteries, and electrochromic devices.

[0005] As a family of polymers, the poly(3,4-alkylenedioxythiophenes)(PXDOTs) have very useful redox switching properties due to theirelectron-rich character which yields very low switching potentials. Theparent polymer of this family, poly(3,4-ethylenedioxythiophene) (PEDOT),has now been developed to the point of commercialization and is used asa stable conducting material in photographic film, tantalum capacitors,and feed through holes in printed circuit boards. In addition,poly(3)3,4-alkylenedioxythiophenes) switch rapidly and efficientlybetween their neutral and p-doped forms with a minimum of side reactionsand long switching lifetimes. Accordingly,poly(3)3,4-alkylenedioxythiophenes) are being heavily investigated for anumber of redox devices including electrochromic applications.

[0006] A key component in many electrochromic and other redox switchingdevices is the formulation of solvent-swollen polymer-supportedelectrolytes. These electrolytes generally consist of a high-boilingplasticizer, a high molecular weight polymer such aspoly(methylmethacrylate) (PMMA), and a lithium salt, such as lithiumbis(trifluoromethylsulfonyl)imide (Li-BTI). Although this formulationworks well, the speed of electroactive switching device is often limitedby the conductivity of the electrolyte formulation and the ability ofthe ions to move into and out of the electroactive polymer layers.

[0007] Since an increase in switching speed of these switching devicesis highly desirable for many applications, new electrolyte formulationsare needed. One such electrolyte formulation to be considered are themolten salts. Electrolytes using the 1-ethyl-3-methyl-1-H-imidazolium(EMI⁺) cation have shown promise as high speed switching devices.Because of its organic nature, the fact that the1-ethyl-3-ethyl-1-H-imidazolium (EMI⁺) cation is less solvated than Li⁺,and the fact that the cation exhibits a relatively large electrochemicalwindow, makes the cation an excellent candidate for use in gelelectrolytes. Furthermore, EMI-BTI is stable up to 300° C., and has anelectrochemical window of 4.3 Volts, both of which are highly desirableproperties in electrolytes.

[0008] It has been suggested that ion-ion interactions in electrolytesprovide the following results: (1) Na⁺ is in a highly complexingenvironment with AICI₄ ⁻, while EMI⁺ is not; (2) salvation for Na⁺ ishigher than EMI⁺ (Na⁺ even distorts the AICI₄ ⁻ anion to some extent);(3) EMI⁺ interacts only weakly with the PF₆ ⁻ anion; (4)dimethylpropylimidizolium cation complexes (via H-bonding) with the Cl⁻anion, but not with the larger AICI₄ ⁻ anion; (5) Li⁺ has a fairly highsalvation energy, even approaching that of water; and (6) oxidativeintercalation of the organic cation into graphite occurs at a potentialthat is negative of that predicted for Li⁺ intercalation. This latterfact might result from lower salvation energy of the organic cationand/or a more stable organic-graphite versus Li⁺-graphite complex.

[0009] Another possible explanation is that since Li⁺ is a smallpolarizing cation where as EMI⁺ is larger and less polarizing, weakercolumbic interactions in the EMI⁺-based electrolytes are present leadingto a higher mobility of EMI⁺. It has been reported that Li⁺ and othercations have a very strong complexing ability, as evidenced by density,molar volummes and thermal expansion coefficients data.

[0010] Not all the above are not direct measurements of salvation energyand columbic interaction differences. However, they do providecompelling evidence that the cations in room temperature liquidelectrolytes are either not as solvated as alkali metal cations, or thecolumbic interactions in EMI⁺-based electrolytes are weaker. Both ofthese theories suggest that molten salt cations would tend to havehigher mobilities. Accordingly, this suggests that devices constructedusing room temperature ionic liquids as the supporting electrolyte wouldtend to switch more rapidly than devices with lithium as the supportingelectrolyte.

SUMMARY OF THE INVENTION

[0011] A charge storage device comprising apoly(3,4-ethylendioxythiophene) (PEDOT) andpoly(3,4-propylenedioxythiophene) (PProDOT) as electrode couples for thecharge storage device and a pair of gel electrolyte layers disposedbetween the electrodes. The gel electrolytes are separated by a batterypaper and are selected from a group consisting of a lithium salt and anorganic electrolyte. The lithium salt used in the present invention islithium bis(trifluoromethylsulfonyl)imide (Li-BTI). The organicelectrolyte used in the present invention is1-ethyl-3-methyl-1H-imidazolium bis(trifluoromethylsulfonyl)imide(EMI-BTI). The electrolyte may also comprise an organic solvent-swollenpolymer wherein the organic solvent-swollen polymer may be, for example,Polymethylmethacrylate swollen with tetraglyme.

[0012] Switching speeds and cycle lifetimes were compared using thelithium salt and the organic electrolyte as the gel electrodes. Theresults indicate that switching speeds, and cyclic lifetimes for theEMI-BTI organic electrolyte are superior to the LI-BTI electrolyte.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 depicts a chemical structure for PProDOT;

[0014]FIG. 2 depicts a chemical structure for PEDOT;

[0015]FIG. 3 illustrates a plot for the cyclic voltammetry responses ofPEDOT/Li-BTI and PEDOT/EMI-BTI;

[0016]FIG. 4 illustrates a plot for the cyclic voltammetry responses ofPProDOT/Li-BTI and PProDOT/EMI-BTI;

[0017]FIG. 5 depicts the charge capacity versus sweep rate ofPProDOT/Li-BTI and PProDOT/EMI-BTI for 0.500 cycles and 5000 cycles.

[0018]FIGS. 5 and 6 depict a schematic diagram for a preferredembodiment of a capacitor comprising the present invention;

[0019]FIG. 7 depicts a current versus voltage plot for EMI-BTI basedcapacitor cycled at 500 mV/s; and

[0020]FIG. 8 depicts a cell lifetime comparison of Li-BTI basedcapacitor and EMI-BTI capacitor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The first step in developing and fabricating a charge storagedevice which may be a supercapacitor or a battery in accordance with apreferred embodiment of the present invention was to synthesize EMI-BTIwhich has the chemical formula 1-ethyl-3-methyl-1H-imidazoliumbis(trifluoromethylsulfonyl)imide. Lithiumbis(trifluoromethylsulfonyl)imide (LI-BTI) is commercially availablefrom 3M Company of St. Paul, Minn.

[0022] A solution of silver bis(trifluoromethylsulfonyl)imide (0.202moles) in 300 mL of ethanol was made by the addition of 23.50 silver (I)oxide (0.101 moles) to a solution of 56.890bis(trifluoromethylsulfonyl)imide (0.202 moles). After dissolution wascomplete, a solution of 29.78 N-ethyl-N′-methylimidazolium chloride(0.202 moles) in 50 mL of ethanol was added. The silver chloride wasfiltered off and the filtrate was concentrated under a vacuum to give78.13 grams of a straw colored liquid (99%). The straw colored liquidwas purified by column chromatography on a silica gel eluting with 20%acetonitrile/chloroform (R_(f)=0.62) to give 73.19 grams of a lightcolored oil (93%).

[0023] The material was characterized using H, C and F nuclear magneticresonance (NMR) spectroscopy as well as infrared spectroscopy. Theresults for H NMR spectroscopy were as follows: ¹H (CD₃CN) : 8.40, s, H;7.37, t, 1H; 7.32, t, 1H; 4.16, q, 2H; 3.81, s, 3H; 1.45, t, 3H. Theresults for C NMR spectroscopy were as follows: C (CD₃CN) : 136.7,124.7, 123.1, 121.1 (q, J=321 Hz)-7 45.9, 36.9, 15.5. The results for FNMR spectroscopy were as follows: F (CD₃CN); −77.9, s. The results ofinfrared spectroscopy were as follows: 3160, 3123, 1574, 1471, 1352,1333, 1227, 1195, 1057, 790, 762, 740, 650, 617, 602, 571, 514.

[0024] Elemental analysis was also performed to determine residualsilver content. All samples were found to have silver content below thedetection limit (0.01% by weight).

[0025] The next step in fabricating the charge storagedevice/supercapacitor was to conduct electrochemical studies as ascreening method for the use of LI-BTI and EMI-BTI as supportingelectrodes for the charge storage device/supercapacitor. The polymer[poly(propylene dioxythiophene) (PProDOT)] was deposited using cyclicvoltammetry from −0.7 to 1.5 V at 100 mV/s from a 0.02 M solution ofpropylene dioxythiophene (PProDOT) in 1.5 M Li-BTI in propylenecarbonate (PC). Unless otherwise noted, all electrochemistry describedis reported vs Ag wire.

[0026] After deposition, the working electrodes were removed and rinsedwith a fresh monomer-free solution of 1.5 M of Li-BTI in , and then thepolymer was cycled using monomer-free 1.5 M Li-BTI in propylenecarbonate. The films were cycled from −0.5 to +1.0 V at 50, 100, 200,400, 600, 800, and 1000 mV/s in order to get a baseline response oftheir electrochemical properties. Films were then cycled at 100 mV/s fora total of 500 and 5000 cycles, and their CV response analyzed after therespective number of cycles was reached. The total amount of charge(cathodic or anodic) was obtained from a current versus time trace foreach sweep speed. Results for both electrolyte systems were normalizedversus the total charge obtained for the respective fresh film (0cycles) at 50 mV/s. Polymer films were then deposited and analyzed withthe same procedures and conditions using EMI-BTI as the electrolyte.

[0027] Referring to FIGS. 1, 2, 6 and 7, a thin film 20 of PEDOT (FIG.2) was electrochemically deposited as a 0.15 micrometer thick film on a92 mm² gold electrode 24. In a like manner, a thin film 26 of PProDOT(FIG. 1) was electrochemically deposited on a 0.15 micrometer thick filmon a 92 mm² gold electrode 28.

[0028] For the PProDOT electrode 26 which is the anode of thesupercapacitor 30, the PProDOT polymer was fully oxidized at +0.5 V,rinsed with a monomer free propylene carbonate (PC)-based electrolytesolution and carefully blotted dry with lint-free paper. The PProDOTpolymer was next coated with a gel electrolyte layer 32 which comprised70% tetraethylene glycol dimethyl ether, 20% ultra high molecular weightPMMA and 10% EMI-BTI. A sheet of 20 μm thick battery separator paper 34was placed on the electrolyte layer, and an additional electrolyte wasadded to sufficiently wet the battery separator paper 34.

[0029] Battery paper 34 separates the conductive polymer layers 20 and26 of the capacitor 30 (cathode and anode) which keeps the conductivepolymer layers from being in electrical conduct with one another andshorting out.

[0030] For the PEDOT electrode 20 which is the cathode of thesupercapacitor 30, the polymer was fully neutralized at −0.5 V, rinsedwith the monomer-free electrolyte solution, carefully blotted dry andcoated with the gel electrolyte (which the gel electrolyte layer 38 inFIG. 6) in the same manner as the PProDOT electrode 26. The twoelectrodes were then pressed together and held in place with a 100-gramweight. Excess electrolyte was removed by blotting with lint-free tissuepaper.

[0031] Testing of the charge storage device/supercapacitor was performedin a laboratory atmosphere using a 2-electrode cyclic voltammetry 36having the reference and working electrode shorted together.Supercapacitors were equilibrated for 10 seconds at 0 Volts, then rampedto 0.5 Volts at 100 and 1000 mV/sec.

[0032] Schematics for the PEDOT/PProDOT supercapacitors studied aregiven in FIGS. 6 and 7. As fabricated, the PProDOT electrode 26 isinitially set in a p-doped (fully oxidized) form and laminated with aneutral PEDOT film to set the initial charged state of thesupercapacitor 30. Charge neutralization of the p-doped PProDOTelectrode 26 proceeds with concurrent oxidation of the PEDOT electrode20 in the supercapacitor 30. As equivalent amounts of polymer weredeposited on each electrode 20 and 26, the supercapacitor discharges toa partially-oxidized PProDOT^(1/2+) and a partially oxidizedPEDOT^(1/2+) as depicted in FIG. 7. Cycling the potential of voltammetry36 leads to switching of the supercapacitor 30 between the charged anddischarged states.

[0033] Referring to FIGS. 3, 4 and 6, the cyclic voltammetry responsesof PEDOT/Li-BTI, PEDOT/EMI-BTI, PProDOT/Li-BTI and PProDOT/EMI-BTI,performed at 100 mV/s, are shown in FIGS. 3 and 4, respectively. Asshown in FIG. 3, PEDOT/Li-BTI which is plot 40 and PEDOT/EMI-BTI whichis plot 42 have similar E_(1/2) potentials versus Ag (silver) wire. Asshown in FIG. 4, PProDOT/Li-BTI which is plot 44 and PProDOT/EMI-BTIwhich is plot 46 also have similar E_(1/2) potentials versus silverwire. As shown in FIG. 4, the peaks in the cyclic voltammetry responseof PProDOT/Li-BTI (plot 44) and PProDOT/EMI-BTI (plot 46) are similar inshape, with the peaks in the oxidative wave of PProDOT/EMI-BTI beingslightly better defined. As shown in FIG. 3, the peaks in the responseof PEDOT/EMI-BTI (plot 42) are more well-defined than those in thecyclic voltammetry response of PEDOT/Li-BTI (plot 40). The resultsillustrated in FIGS. 3 and 4 suggest faster and cleaner transportprocesses with the EMI cation.

[0034] Referring to FIG. 5, the cation dependence of the redox switchinglifetime and rates were measured with the measurements being illustratedin FIG. 5. PProDOT films which were 100 nm thick with a capacity ofapproximately 1.5 mC were measured by cyclic voltammetry as a functionof scan rate. Cycling from −0.5 V to +1.0 V at sweep rates ranging from50 mV/s to 1000 mV/s was carried out and the charge required forswitching was measured. FIG. 5 shows the normalized charge capacity ofthe PProDOT film as a function of sweep rate in the two electrolytesLi-BTI and EMI-BTI.

[0035] Specifically, plot 48 depicts charge capacity versus sweep ratefor Li-BTI at 0 cycles; plot 50 depicts charge capacity versus sweeprate for EMI-BTI at 0 cycles; plot 52 depicts charge capacity versussweep rate for Li-BTI at 500 cycles; plot 54 depicts charge capacityversus sweep rate for Li-BTI at 5000 cycles; plot 56 depicts chargecapacity versus sweep rate for EMI-BTI at 500 cycles; and plot 58depicts charge capacity versus sweep rate for EMI-BTI at 5000 cycles.

[0036] As shown in FIG. 5, the charge capacities are essentiallyidentical at low switching speeds of up to about 150 mV/s. At higherswitching speeds, it is evident that the EMI-based electrolyte allowsmore rapid switching and, thus, can retain a higher level of charge atany specific switching rate. While the overall charge density that canbe attained decreases as a function of scan rate, PProDOT/EMI-BTI passesabout 80% more charge than Li-BTI at the highest sweep rate.

[0037] A determination was also made as to which ion is most dominant intransport during redox switching. In most instances, using relativelysmall, non-nucleophilic anions, the PXDOT family shows anion dominanttransport. In this instance, though, the relatively large organic BTIanion has the possibility of being entrapped and retained in theconducting polymer membrane, thus forcing at a least a portion of thetransport to be due to the cation. External and internal transportnumbers which are calculated indicate that organic cations may functionas charge carriers. The actual transport mechanism in these systems islikely complex and best described as mixed transport from both ions.This is confirmed by the large difference in the electrochemicalresponse time for these two different cations.

[0038] This ion transport effect holds as a function of switchinglifetimes as evidenced by the charge capacity results shown for PProDOTin FIG. 5 after 500 and 5000 cycles, respectively. In both instances asshown by plot 56 at 500 cycles and plot 58 at 5000 cycles,PProDOT/EMI-BTI is shown to pass significantly more charge, that is havea substantially higher charge capacity. As the films have now had theirelectrochemistry “broken in”, it can be seen by plot 50 that the chargecapacity is also higher using EMI-BTI at the lower sweep rate of 0cycles. This suggests that, after conditioning of the film, the cationtransport becomes even more important to the mechanism of redoxswitching.

[0039] The results shown in FIG. 5 demonstrate that the EMI⁺ ion istransported faster than the Li⁺ ion and significantly more chargecapacity is maintained as a function of the number of cycles. Thissuggests that the EMI-BTI electrolytes may prove more suitable in gelelectrolytes for electroactive polymer charge storagedevices/supercapacitors.

[0040] While the cyclic voltammetric results depicted in FIG. 5 proveuseful as a valuable screening tool, it is understood that the counterhalf-cell reactions are, at best, not well-defined. In order to make amore rigorous comparison, two-electrode supercapacitors were fabricatedin accordance with the present invention and their performance measuredas a function of electrolyte.

[0041] Referring to FIGS. 6 and 8, the columbic efficiency of thesupercapacitor 30 versus overall cell voltage was analyzed. Beyond anoverall cell voltage of 0.5 Volts, the storage capacity ofsupercapacitor 30 only increased slightly, i.e. a 3% increase at 1.0 V.The columbic efficiency of supercapacitor 30 decreased dramaticallybeyond 0.6 Volts and showed a nearly linear drop from 95% efficiency at0.5 Volts to 75% efficiency at 1.0 Volts. Therefore it was decided that0.5 Volts was the best trade-off between columbic efficiency and overallcell voltage. After first equilibrating the supercapacitor for 10seconds at 0.0 V applied, the supercapacitor was cycled up to an appliedvoltage of 0.5 V and back at various cycling rates. FIG. 5 shows thecurrent versus voltage characteristic of an ionic liquid-based EMI-BTIbased supercapacitor cycled at 500 mV/s.

[0042] The distinct capacitive nature of the charge storage forsupercapacitor 30 is evident from the plot 60 of FIG. 8 as there is arapid increase in current upon application of a voltage potentialfollowed by a long plateau in the plot 60. Reversal of the appliedvoltage/reverse scanning represented by the plot's return path(designated generally by the reference numeral 62) then shows dischargeof the stored charge as the supercapacitor returns to its originalstate. At relatively slow scan rates (100-500 mV/s) the capacitymeasured was nearly scan rate independent at around 1.25 mC (a chargedensity of 1.35 mC/cm²). Even cycling at rates of up 5000 mV/s gave onlyan approximate 20% decrease in the total charge capacity. These resultsindicate that the supercapacitor switched rapidly.

[0043] Estimating the mass of the polymer films on the electrodes 20 and26 to be 2×10⁻⁵ g, the capacity of supercapacitor 30 was found to beapproximately 65 C/g. The capacity of PProDOT electrode 26 is calculatedto be about 150 C/g (4 repeat units/electron) and 200 C/g (3 repeatunits/electron). The capacity of PEDOT electrode 20 is calculated to beabout 165 C/g (4 repeat units/electron) and 220 C/g (3 repeatunits/electron).

[0044] A Type I supercapacitor uses 50% of the polymer capacity.Therefore, 65 C/g is comparable to what is expected for aPEDOT/PProDOT-based Type I supercapacitor. Polyaniline has a calculatedcapacity of 500 C/g (250 C/g in a Type I supercapacitor).

[0045] The charge capacity for a lithium-based supercapacitor was foundto be around 1.75 mC (charge density of 1.90 mC/cm²). Althoughquantitative comparisons are difficult (the higher capacity of thesedevices suggests a thicker polymer film), the capacity of the lithiumbased supercapacitor was found to depend upon the scan rate. Thecapacity decreased by almost 30% when going from 100 to 500 mV/s. Theseresults are consistent with cyclic voltammetry studies.

[0046] Referring to FIGS. 6 and 9, to determine cell lifetimes forLi-BTI based supercapacitors and EMI-BTI based supercapacitors, thecharge capacities were measured as a function of a number of cycles upto 50,000 full cycles where a cycle is defined as scanning from 0.0 to0.5 V and back to 0.0 V. As shown in FIG. 9, the EMI⁺-based electrolyteas represented by plot 70 shows significant enhancement in celllifetimes when compared to the Li⁺ electrolyte as represented byreference numeral 72.

[0047] After 50,000 cycles, the PEDOT/PProDOT supercapacitor retained upto 98% of its initial charge capacity using the EMI⁺ electrolytes, whilethere was a decrease in charge capacity of about 30% using a lithiumsalt, i.e. Li-BTI based capacitor. These results may prove especiallyimportant in the use of organic electrolytes in gel systems for PXDOTsupercapacitors. It is possible that hundreds of thousands of cycles arenow obtainable using gel systems for PXDOT supercapacitors. Given thefact that the neutral form of PEDOT is known to be air-sensitive due toits low oxidation potential, it is evident that this is not limitingcell life.

[0048] At this time it should be noted that the electrolyte may alsocomprise an organic solvent-swollen polymer wherein the organicsolvent-swollen polymer may be, for example, Polymethylmethacrylateswollen with tetraglyme.

[0049] At this time, it should also be noted that the PProDOT/PEDOTtechnology used in making the present invention can also be used infabricating batteries or any other charge storage device.

[0050] From the above, it is evident that PProDOT/PEDOT charge storagedevice/supercapacitors have been constructed using gel electrolytescomposed of lithium and an organic (EMI⁺) electrolyte switch quiterapidly and store similar amounts of charge. The EMI⁺ basedsupercapacitor, however, is significantly superior in cycle lifetime.These results have implications that go well beyond the specificpolymers and devices described and tested herein. Numerous conductingpolymers can be envisioned in electroactive devices and the use of theseelectrochemically stable organic cations may greatly enhance theirswitching lifetimes. In addition to battery and supercapacitor chargestorage systems, these electrolytes may find useful in electrochromicdisplays which long lifetimes are desired.

What is claimed is:
 1. A polymer based charge storage device comprising:(a) a pair of spaced apart electrodes, a first electrode of said pair ofelectrodes consisting of a PProDOT polymer and a second electrode ofsaid pair of electrodes consisting of a PEDOT polymer, said firstelectrode being an anode for said polymer based charge storage deviceand said second electrode being a cathode for said polymer based chargestorage device; (b) a first electrolyte gel and a second electrolyte geldisposed between said pair of spaced apart electrodes; and (c) a batterypaper positioned between said first electrolyte gel and said secondelectrolyte gel to separate said cathode for said polymer based chargestorage device from said anode for said polymer based charge storagedevice.
 2. The polymer based charge storage device of claim 1 whereinsaid PProDOT polymer consist of poly(3,4-propylenedioxythiophene). 3.The polymer based charge storage device of claim 1 wherein said PEDOTpolymer consist of poly(3,4-ethylendioxythiophene).
 4. The polymer basedcharge storage device of claim 1 wherein said first and secondelectrolyte gels comprise organic solvent-swollen polymers.
 5. Thepolymer based charge storage device of claim 4 wherein said organicsolvent-swollen polymer comprises Polymethylmethacrylate swollen withtetraglyme.
 6. The polymer based charge storage device of claim 1wherein said first and second electrolyte gels comprise lithiumbis(trifluoromethylsulfonyl)imide (Li-BTI).
 7. The polymer based chargestorage device of claim 1 wherein said first and second electrolyte gelscomprises 1-ethyl-3-methyl-1H-imidazoliumbis(trifluoromethylsulfonyl)imide (EMI-BTI).
 8. The polymer based chargestorage device of claim 1 wherein a first capacitor having said firstand second electrolytes comprising EMI-BTI has a substantially longercell lifetime when compared to a second capacitor having said first andsecond electrolytes comprising said Li-BTI.
 9. The polymer based chargestorage device of claim 8 wherein said first capacitor having said firstand second electrolytes comprising said EMI-BTI has a switching speedwhich is substantially equal to a switching speed of said secondcapacitor having said first and second electrolytes comprising saidLi-BTI.
 10. The polymer based charge storage device of claim 1 whereinsaid polymer based charge storage device comprises a supercapacitor. 11.The polymer based charge storage device of claim 1 wherein said polymerbased charge storage device comprises a battery.
 12. A polymer basedcapacitor comprising: (a) a pair of spaced apart electrodes, a firstelectrode of said pair of electrodes comprisingpoly(3,4-propylenedioxythiophene) and a second electrode of said pair ofelectrodes comprising poly(3,4-ethylendioxythiophene), said firstelectrode being an anode for said capacitor and said second electrodebeing a cathode for said capacitor; (b) a first electrolyte gel and asecond electrolyte gel disposed between said pair of spaced apartelectrodes; (c) a battery paper positioned between said firstelectrolyte gel and said second electrolyte gel to separate said cathodefor said capacitor from said anode for said capacitor; and (d) saidfirst electrolyte gel and said second electrolyte gel comprising1-ethyl-3-methyl-1H-imidazolium bis(trifluoromethylsulfonyl)imide(EMI-BTI).
 13. The polymer based capacitor of claim 12 wherein saidcapacitor retains approximately 98% of charge capacity for saidcapacitor as a function of 50,000 cycles where a cycles is a scanning of0.0 volts to 0.5 volts and a return to 0.0 volts.
 14. A polymer basedcapacitor comprising: (a) a pair of spaced apart electrodes, a firstelectrode of said pair of electrodes comprisingpoly(3,4-propylenedioxythiophene) and a second electrode of said pair ofelectrodes comprising poly(3,4-ethylendioxythiophene), said firstelectrode being an anode for said capacitor and said second electrodebeing a cathode for said capacitor; (b) a first electrolyte gel and asecond electrolyte gel disposed between said pair of spaced apartelectrodes; (c) a battery paper positioned between said firstelectrolyte gel and said second electrolyte gel to separate said cathodefor said capacitor from said anode for said capacitor; and (d) saidfirst electrolyte gel and said second electrolyte gel comprising alithium salt.
 15. The polymer based capacitor of claim 14 wherein saidlithium salt comprises lithium bis(trifluoromethylsulfonyl)imide(Li-BTI).
 16. The polymer based capacitor of claim 14 wherein saidcapacitor retains approximately 70% of charge capacity for saidcapacitor as a function of 50,000 cycles where a cycles is a scanning of0.0 volts to 0.5 volts and a return to 0.0 volts.
 17. A method formaking a polymer based charge storage device comprising the steps of:(a) electrochemically depositing a thin film of a PEDOT polymer on afirst electrode to form a cathode for said polymer based charge storagedevice and a thin film of PProDOT polymer on a second electrode to forma cathode for said polymer based charge storage device; (b) oxidizingsaid PProDOT polymer at a voltage of about +0.5 volts; (c) neutralizingsaid PEDOT polymer at a voltage of about −0.5 volts; (d) rinsing saidPEDOT polymer and said PProDOT polymer with a monomer free propylenecarbonate (PC)-based electrolyte solution; (e) blotting said PEDOTpolymer and said PProDOT polymer with a lint free paper; (f) coatingsaid PEDOT Polymer with an electrolyte gel to form a first electrolytegel layer within said polymer baseed charge storage device; (g) coatingsaid PEDOT Polymer with said electrolyte gel to form a secondelectrolyte gel layer within said polymer based charge storage device;and (h) separating said anode from said cathode within said polymerbased charge storage device by placing a battery paper between saidfirst electrolyte gel layer and said second electrolyte gel layer. 18.The method of claim 17 further comprising the step of connecting a2-electrode cyclic voltammetry to the cathode and anode of said polymerbased charge storage device to measure performance parameters for saidpolymer based charge storage device including current voltagecharacteristics of said polymer based charge storage device and celllifetime for said polymer based charge storage device.
 19. The method ofclaim 17 wherein said monomer free propylene carbonate (PC)-basedelectrolyte solution comprises a solution having approximately 90%propylene carbonate and 10% lithium salt.
 20. The method of claim 17wherein said monomer free propylene carbonate (PC)-based electrolytesolution comprises a solution having approximately 90% propylenecarbonate and 10% EMI-BTI.
 21. The method of claim 17 wherein said firstand second electrodes comprise a 92 mm² gold electrode.
 22. The methodof claim 17 wherein said PEDOT polymer consist ofpoly(3,4-ethylendioxythiophene).
 23. The method of claim 17 wherein saidelectrolyte gel comprises 70% tetraethylene glycol dimethyl ether, 20%poly(methylmethacrylate) and 10% 1-ethyl-3-methyl-1H-imidazoliumbis(trifluoromethylsulfonyl)imide (EMI-BTI).
 24. The method of claim 17wherein said electrolyte gel comprises a molten salt electrolyte. 25.The method of claim 17 wherein said electrolyte gel comprises anEMI-cation based electrolyte.
 27. The method of claim 17 wherein saidpolymer based charge storage device comprises a super capacitor.
 28. Themethod of claim 17 wherein said polymer based charge storage devicecomprises a battery.